Singer, M. | bioRxiv Science

bioRxiv2018

Cationic charge and polyspecificity of an integrin domain regulates infectivity of malaria parasites

Cell-cell and cell-substrate adhesion is critical for many functions in life. In eukaryotes, I-domains mediate functions as divergent as tissue traversal by malaria-causing Plasmodium parasites as well as cell adhesion and migration by human leucocytes. The I-domain containing protein TRAP is important for Plasmodium sporozoite motility and invasion. Here we show that the I-domain of TRAP is required to mediate adhesional properties which can be partially preserved when the native I-domain is replaced by I-domains from human integrins or from an apicomplexan parasite that does not infect insects. By putting in vivo data and structural features in perspective we conclude that polyspecificity and positive charge around the ligand binding site of the I-domain are important for TRAP function. Our data suggest a highly preserved functionality of I-domains across eukaryotic evolution that is used by apicomplexan parasites to invade a broad range of tissues in a variety of hosts.

microbiology↗

bioRxiv2017

The Effects of Practice-based Training on Graduate Teaching Assistants’ Classroom Practices

Evidence-based teaching is a highly complex skill, requiring repeated cycles of deliberate practice and feedback to master. Despite existing well characterized frameworks for practice-based training in K-12 teacher education, the major principles of these frameworks have not yet been transferred to instructor development in higher educational contexts, including training of graduate teaching assistants (GTAs). We sought to determine whether a practice-based training program could help GTAs learn and use evidence-based teaching methods in their classrooms. We implemented a weekly training program for introductory biology GTAs, which included structured drills of techniques selected to enhance student practice, logic-development, and accountability and reduce apprehension. GTAs received regular performance feedback based on classroom observations. To quantify use of target techniques and levels of student participation, we collected and coded 160 hours of video footage. We found that, although GTAs adopted and utilized many of the target techniques with high frequency, techniques which enforced student participation were not stably adopted and their use was unresponsive to formal feedback. We also found that techniques discussed in training, but not practiced, were not used at quantifiable frequencies, further supporting the importance of practice-based training for influencing instructional practices.

scientific communication and education↗